In water treatment systems, a liquid/polymer solution is typically used to coagulate or flocculate undesired suspended solids in city waste water. More specifically, a polymer (which is made up of electrically charged molecules) is mixed with a liquid and thereby activated. This liquid/polymer solution is then added to a fluid containing suspended solids (i.e. city waste water, generally a sludge) for the coagulation or flocculation of the suspended solids. More particularly, the polymers attach themselves to the suspended solids to form larger particles which may then be effectively removed from the fluid. The proper introduction of polymers into, and the proper mixing of the polymers with, the liquid is usually critical to successfully forming the liquid/polymer solution. On the other hand, overly aggressive introduction and/or mixing may undesirably affect the coagulation/flocculation power of the polymer.
In the past, a typical polymer mixing/activation system included a large mixing/holding tank (i.e., 100 or more gallons). The liquid, such as water was pumped or otherwise transferred to this tank and an emulsion polymer was added. Thereafter, the liquid and the polymer were blended by a slow speed mixer designed for use with the tank whereby the polymers would be activated to form a liquid/polymer solution. After being retained for an appropriate time (i.e., fifteen minutes), the liquid/polymer solution was drained or otherwise removed from the tank for use in water treatment. While such systems proved effective, they required the use of a large mixing/holding tank, a slow speed mixer, and a variable speed chemical dosing pump.
In recent years, automatic polymer mixing/activation systems have been developed which eliminate the need for a large mixing/holding tank. However, these systems still require a chemical dosing pump for the introduction of the polymer. Additionally, such automatic systems usually include mixing devices, such as a flash mixer. Consequently, most polymer mixing/activation systems still require an outside source of power (i.e., electricity) to operate the pump and/or the mixing devices.
Applicants therefore believe that a need remains for polymer mixing/activation systems having components which do not require an outside source of power, such as electricity, to operate. Additionally or alternatively, applicants believe a need remains for more gentle and thorough polymer mixing/activation systems.